Year	Number
2007	10.99946
2008	10.29517
2009	9.96223
2010	9.36292
2011	9.08713
2012	8.68418
2013	8.71161
2014	8.3424
2015	8.35369
2016	8.15128
2017	7.96711
2018	7.79948